EP4260034A1 - Transducteur de pression - Google Patents

Transducteur de pression

Info

Publication number
EP4260034A1
EP4260034A1 EP21820506.0A EP21820506A EP4260034A1 EP 4260034 A1 EP4260034 A1 EP 4260034A1 EP 21820506 A EP21820506 A EP 21820506A EP 4260034 A1 EP4260034 A1 EP 4260034A1
Authority
EP
European Patent Office
Prior art keywords
pressure
pressure sensor
measuring
connection
designed
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
EP21820506.0A
Other languages
German (de)
English (en)
Inventor
Andreas Rossberg
Nils Ponath
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Endress and Hauser SE and Co KG
Original Assignee
Endress and Hauser SE and Co KG
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Endress and Hauser SE and Co KG filed Critical Endress and Hauser SE and Co KG
Publication of EP4260034A1 publication Critical patent/EP4260034A1/fr
Pending legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L9/00—Measuring steady of quasi-steady pressure of fluid or fluent solid material by electric or magnetic pressure-sensitive elements; Transmitting or indicating the displacement of mechanical pressure-sensitive elements, used to measure the steady or quasi-steady pressure of a fluid or fluent solid material, by electric or magnetic means
    • G01L9/0041—Transmitting or indicating the displacement of flexible diaphragms
    • G01L9/0072—Transmitting or indicating the displacement of flexible diaphragms using variations in capacitance
    • G01L9/0075—Transmitting or indicating the displacement of flexible diaphragms using variations in capacitance using a ceramic diaphragm, e.g. alumina, fused quartz, glass
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L19/00—Details of, or accessories for, apparatus for measuring steady or quasi-steady pressure of a fluent medium insofar as such details or accessories are not special to particular types of pressure gauges
    • G01L19/0061—Electrical connection means
    • G01L19/0069—Electrical connection means from the sensor to its support
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L19/00—Details of, or accessories for, apparatus for measuring steady or quasi-steady pressure of a fluent medium insofar as such details or accessories are not special to particular types of pressure gauges
    • G01L19/0061—Electrical connection means
    • G01L19/0084—Electrical connection means to the outside of the housing
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L19/00—Details of, or accessories for, apparatus for measuring steady or quasi-steady pressure of a fluent medium insofar as such details or accessories are not special to particular types of pressure gauges
    • G01L19/14—Housings
    • G01L19/145—Housings with stress relieving means
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L19/00—Details of, or accessories for, apparatus for measuring steady or quasi-steady pressure of a fluent medium insofar as such details or accessories are not special to particular types of pressure gauges
    • G01L19/14—Housings
    • G01L19/147—Details about the mounting of the sensor to support or covering means

Definitions

  • the invention relates to a pressure measuring transducer for measuring a pressure with a pressure sensor, the pressure sensor being arranged in an interior of a sensor housing and being acted upon by a medium under the pressure to be measured through an opening in the sensor housing.
  • Pressure sensors are used in particular in measurement and control technology, as well as in process automation to measure pressure.
  • Pressure sensors can be divided into two groups.
  • One group includes pressure sensors whose pressure sensor can be directly subjected to a pressure to be measured.
  • These pressure measuring transducers comprise ceramic pressure sensors with a rigid base body and a measuring membrane which is arranged on the base body and encloses a pressure chamber and can be deformed by a pressure acting on it. Due to the high chemical and mechanical resistance of ceramics, ceramic pressure sensors can be directly exposed to the medium under the pressure to be measured.
  • the other group includes pressure sensors whose pressure sensor is acted upon by the pressure to be measured via a pressure transmitter connected upstream of the pressure sensor.
  • Pressure transmitters comprise a separating membrane that can be pressurized on the outside, under which a pressure-receiving chamber filled with a pressure-transmitting liquid is enclosed.
  • a pressure transmission line which is also filled with the liquid and via which the pressure is transmitted to the pressure sensor, is connected to the pressure receiving chamber.
  • DE 10 2006 056 173 A1 describes a pressure transmitter with a separating membrane made of stainless steel, on the outside of which a layer of aluminum oxide is arranged.
  • Aluminum oxide has a hydrogen diffusion coefficient that is significantly lower than the hydrogen diffusion coefficients of metallic layers. Accordingly, the aluminum oxide layer acts as a highly effective hydrogen diffusion barrier.
  • measuring membranes of ceramic pressure sensors made entirely of ceramic form a significantly better and longer-lasting protection against hydrogen diffusion due to the low hydrogen diffusion rate in ceramic.
  • Ceramic pressure sensors are usually clamped in a sensor housing in such a way that only their measuring membrane can be acted upon by the medium that is under the pressure to be measured through an opening in the sensor housing.
  • a clamping device is usually used for this purpose, in which an outer edge of the pressure sensor with the interposition of a the interior of the sensor housing against the medium sealing seal is clamped in the sensor housing in such a way that the measuring membrane can be acted upon through an opening in the sensor housing with the medium under the pressure to be measured.
  • An example of this is described in DE 103 34 854 A1.
  • these pressure sensors can usually only be used to measure pressures in a pressure measuring range of less than or equal to 100 bar. With special precautions, especially with regard to the clamping, higher pressures, eg pressures of up to 400 bar, can also be measured under certain circumstances.
  • sealing materials that can be used to seal the interior of the sensor housing from the medium acting on the measuring membrane are not diffusion-tight. This means that the hydrogen contained in the medium can penetrate into the interior of the sensor housing almost unhindered. For reasons of explosion protection, this is undesirable or even impermissible, particularly in the case of pressure measuring transducers used in areas at risk of explosion.
  • the problem of diffusion tightness can be countered by mounting the pressure sensor in the sensor housing using a diffusion-tight joint.
  • An example of this is described in the German patent application DE 10 2018 123041 A.
  • the pressure measuring transducer described there comprises a ceramic pressure sensor which is arranged in an interior space of a sensor housing and can be acted upon by a medium which is under the pressure to be measured through an opening in the sensor housing.
  • the sensor housing is a support made of titanium, which includes a free-standing, tubular support area running parallel to the surface normal to the measuring membrane.
  • An exemplary embodiment provides that the end region of the carrier opposite the opening has a radially inwardly extending shoulder adjoining the tubular carrier region at the end.
  • an outer edge of an end face facing the shoulder of a rigid base body connected to a measuring membrane, including a pressure chamber, is connected by means of a diffusion-tight joint to an inner edge area of the shoulder spaced apart from the tubular support area.
  • An end area of the carrier opposite the shoulder is connected to a process connection made of stainless steel, via which the interior of the carrier can be subjected to the pressure to be measured.
  • the tubular carrier area is used for the thermo-mechanical decoupling of the pressure sensor and the process connection. For this purpose, it preferably has a small wall thickness of 1 mm to 2 mm.
  • the pressure measuring range of this pressure sensor is limited to low pressures, such as pressures of less than or equal to one bar.
  • One reason for this is the limited compressive strength of the ring-shaped joint, which is only exposed to the pressure to be measured on the outside.
  • the invention comprises a pressure transducer for measuring a pressure with a pressure sensor, the pressure sensor being arranged in an interior space of a sensor housing and being acted upon through an opening in the sensor housing by a medium which is under the pressure to be measured, which is characterized in that the Pressure sensor: is mounted on connecting elements that protrude into the interior and are freestanding in the interior in such a way that the pressure sensor is exposed to the pressure prevailing in the interior on all sides, comprises two measuring bodies which are connected to one another by enclosing a pressure chamber and can each be deformed by the pressure acting on it, and an electromechanical converter includes, which converts a mechanical variable dependent on a sum of the pressure-dependent deformations of both measuring bodies into a metrologically detectable electrical measured variable.
  • Pressure sensors according to the invention offer the advantage that the mechanical connections between the pressure sensor and the connection elements are practical even at very high pressures due to the pressure acting on the pressure sensor on all sides in the interior essentially isostatically and equally on the outside on all sides on the connection elements that are freestanding in the interior and connected to the pressure sensor are not exposed to any appreciable or only very small forces. This is the case in particular because the pressure acting on the opposite side of the respective connecting element or the respective mechanical connection of the same magnitude counteracts the pressure acting externally on one side of the connecting elements and the mechanical connections. This pressure also acts in the same way on the pressure sensor, so that practically no tensile or shearing stresses are exerted on the mechanical connections due to the pressure acting on the pressure sensor.
  • a further advantage is that with appropriate dimensioning of the two measuring bodies connected to one another, very high pressures, for example pressures in a pressure measuring range of up to 1000 bar or even above, can also be measured. Since the pressure sensor in the interior is directly exposed to the medium under the pressure to be measured, the achievable measurement accuracy is not impaired by the pressure- and temperature-dependent pressure transmission behavior of a pressure transmitter connected upstream of the pressure sensor.
  • the two measuring bodies that can be deformed by the pressure acting on them offer the advantage that the pressure is measured using the sum of the pressure-dependent deformations of both measuring bodies.
  • a high measuring accuracy can thus still be achieved if the thickness of both measuring bodies is dimensioned in such a way that the measuring bodies can withstand overloads exceeding a measuring range upper limit of a pressure measuring range of the pressure sensor.
  • a higher upper measuring range limit can of course also be used. In this case, the overload resistance is reduced accordingly with regard to overloads that exceed the higher upper limit of the measuring range.
  • connection elements or each connection element is designed as an electrically conductive connection line, the end of which is connected by means of an electrically conductive mechanical connection to an associated electrical connection of the pressure sensor, each arranged on an outside of the pressure sensor and each connecting element designed as a connecting line is guided through the housing wall through a pressure-resistant bushing inserted into a housing wall of the sensor housing and is electrically insulated from the housing wall.
  • each bushing is designed as a hydrogen-diffusion-tight bushing, is designed as a ceramic bushing or as a glass bushing, and/or as pressures exceeding an upper measuring range limit of the pressure sensor, as pressures exceeding an overload resistance of the pressure sensor and/or is designed as a pressure-resistant bushing with respect to pressures of up to 1700 bar or up to 2000 bar.
  • each feedthrough is arranged in a housing wall area of the sensor housing that is opposite the opening.
  • a second further development is characterized in that the sensor housing surrounding the interior: consists of metal or high-grade steel, is impermeable to hydrogen diffusion, and/or as compared to pressures exceeding an upper limit of the measuring range of the pressure sensor, as with respect to pressures exceeding an overload resistance of the pressure sensor and/or as a sensor housing which is pressure-resistant with respect to pressures of up to 2000 bar.
  • a third development is characterized in that the pressure sensor is connected to one end of each connection element by means of a mechanical connection, by means of a mechanical, electrically conductive connection or a connection designed as soldering in such a way that the connection on the outside can withstand the pressure prevailing in the interior on all sides is exposed.
  • connection elements are designed as straight, curved or rod-shaped elements having a different shape, have a free-standing length of 1 mm to 10 mm in the interior, have a diameter of 0.25 mm to 3 mm and /or have a cross-sectional area of 0.05 mm 2 to 7 mm 2 , are designed as metallic connection elements made of Kovar®, stainless steel, nickel, copper, a nickel-iron alloy, a copper-nickel alloy, molybdenum, Alumel® or constantan, and/or surrounded by a jacket or insulation.
  • a fifth further development is characterized in that the pressure sensor is designed as an absolute pressure sensor, which measures the pressure acting on the two measuring bodies as absolute pressure compared to an internal pressure prevailing in the pressure chamber, an internal pressure designed as vacuum pressure or an internal pressure of the order of 1 bar , and the two measuring bodies are connected to one another via a pressure-resistant connection or a pressure-resistant and hydrogen-diffusion-tight connection, the connection surrounding the pressure chamber on all sides on the outside.
  • the two measuring bodies are made of glass and are connected to one another via a connection surrounding the pressure chamber on all sides on the outside or a connection comprising a glass ring and/or a glass soldering that surrounds the pressure chamber on the outside, or the two measuring bodies are made of metal or stainless steel and are connected to one another via a connection surrounding the pressure chamber on all sides on the outside or a connection comprising a weld surrounding the pressure chamber on all sides on the outside, or the two measuring bodies are made of ceramic and are connected to one another via a connection surrounding the pressure chamber on all sides on the outside, with the Connection: is designed as active brazing or as glass soldering, or comprises a ring or a ring designed as a ceramic ring, the ring: either with each of the two measuring bodies via a hydrogen-diffusion-tight joint or r a joint designed as a weld produced by means of a laser welding process is connected in a hydrogen-diffusion-tight manner, or is designed as part of one of the
  • Measuring body is connected in a hydrogen diffusion-tight manner via a hydrogen-diffusion-tight joint or a weld formed as a weld produced by means of a laser welding process.
  • a sixth development is characterized in that the converter of the pressure sensor is connected via the connection elements to sensor electronics arranged outside of the sensor housing, which are designed to provide a measurement signal representing a pressure measured by means of the pressure sensor.
  • a seventh development is characterized in that the transducer comprises a measuring electrode arranged on an inside of one of the two measuring bodies, which together with a counter-electrode arranged on an inside of the other measuring body facing this measuring body, has a capacitor with a value that depends on the sum of the pressure-dependent deformations of both measuring bodies dependent measuring capacitance, and the measuring electrode and the counter-electrode are each electrically conductively connected to a connection arranged on an outside of the pressure sensor via a connection line running through one of the two measuring bodies or a contact pin running through one of the two measuring bodies.
  • a development of the seventh development is characterized in that the contact pin, which is electrically conductively connected to the counter-electrode arranged on the inside of one of the two measuring bodies: runs through the other measuring body opposite the counter-electrode, and either via an electrically conductive connecting the two measuring bodies to one another Connection is electrically conductively connected to the counter-electrode, or extends through a connection connecting the two measuring bodies to an area of the counter-electrode which adjoins an end face of the connection which faces away from the measuring body surrounding the contact pin.
  • measuring bodies are made of ceramic, glass, metal or stainless steel.
  • a further development is characterized in that the pressure sensor is designed to measure pressures in a pressure measuring range of greater than or equal to 400 bar and/or less than or equal to 1000 bar, and/or the pressure sensor as an overload exceeding an upper measuring range limit of the pressure sensor from to up to 1800 bar or up to 5500 bar overload-resistant pressure sensor is formed.
  • the measuring bodies are designed as essentially disc-shaped or as structurally identical essentially disc-shaped measuring bodies, which each have a base area of 200 mm 2 to 1300 mm 2 and/or a thickness of 5 mm to 10 mm .
  • Fig. 1 shows: a pressure transducer
  • FIG. 2 shows: an alternative embodiment of a connection of the two measuring bodies from FIG. 1 ;
  • FIG. 3 shows: an inside of one of the measuring bodies from FIG. 1 ;
  • Fig. 5 shows: a metallic pressure sensor.
  • FIG. 1 shows a pressure sensor with a sensor housing 1 and a pressure sensor 5 arranged in an interior 3 of the sensor housing 1.
  • the pressure sensor 5 can be acted upon through an opening 7 in the sensor housing 1 with a medium under the pressure p to be measured.
  • the pressure sensor 5 is mounted in the interior 3 on connecting elements 9 that protrude into the interior 3 and are freestanding in the interior 3 in such a way that the pressure sensor 5 is exposed to the pressure p prevailing in the interior 3 on all sides.
  • the pressure sensor 5 comprises two measuring bodies 13, 15 which are connected to one another and include a pressure chamber 11 and are each deformable by the pressure p acting on them.
  • This highly symmetrical sensor structure offers the advantage that both measuring bodies 13, 15 contribute equally to the overload resistance of the pressure sensor 5, so that with appropriate dimensioning of both measuring bodies 13, 15 a correspondingly higher overload resistance of the pressure sensor 5 can be achieved.
  • pressure-dependent deformable measuring bodies of different thicknesses can also be used.
  • the pressure sensor 5 shown as an example in FIG. 1 is designed as a ceramic pressure sensor.
  • An oxide ceramic such as aluminum oxide (Al2O3), is suitable as the ceramic of the pressure sensor 5, with both measuring bodies 13, 15 preferably being made of the same ceramic.
  • the pressure sensor 5 comprises an electromechanical converter which converts a mechanical variable dependent on a sum of the pressure-dependent deformations of both measuring bodies 13, 15 into a metrologically detectable electrical measured variable.
  • This electrical measured variable can be measured, for example by means of sensor electronics 17 that can be connected or are connected to the converter, and can be converted into a measurement signal that reflects the measured pressure.
  • the sensor electronics 17 can optionally be arranged either inside or, as shown in FIG. 1, outside of the interior 3 of the sensor housing 1 .
  • An arrangement of the sensor electronics 17 outside of the sensor housing 1 offers the advantage that the sensor electronics 17 are not exposed to the pressures prevailing in the sensor housing 1 and therefore no corresponding flameproof encapsulation of the sensor electronics 17 is required.
  • Fig. 1 shows a capacitive converter as an example, which comprises a measuring electrode 19 arranged on an inner side of one of the two measuring bodies 13, which together with a counter-electrode 21 arranged on an inner side of the other measuring body 15 facing this measuring body 13, forms a capacitor with a sum of forms the pressure-dependent deformations of both measuring bodies 13, 15 dependent measuring capacitance C p .
  • the sensor electronics 17 include, for example, a capacitance measuring circuit connected to the capacitor, which outputs a measurement signal corresponding to the measured capacitance C p .
  • the converter can additionally include a reference capacitor with an essentially pressure-independent reference capacitance Cref.
  • This measured variable has a more linear dependency on the pressure p to be measured and a lower temperature dependency than the measuring capacitance C p .
  • a differently designed capacitive converter or a converter based on a different converter principle e.g. a resistive or an optical converter, can also be used.
  • Pressure measuring transducers according to the invention have the advantages already mentioned at the outset.
  • individual components of the pressure measuring transducer can each have different configurations that can be used individually or in combination with one another.
  • the sensor housing 1 consists of a metal, such as stainless steel.
  • the interior 3 of the sensor housing 1 is surrounded, for example, by a hydrogen-diffusion-tight, pressure-resistant housing wall 25 .
  • the pressure resistance of the sensor housing 1 is higher, the greater the wall thickness of the housing wall 25 is.
  • the compressive strength can also be increased by the shape of the housing wall 25.
  • the sensor housing 1 is designed, for example, as a pressure p exceeding an upper limit of the measuring range of the pressure sensor 5, as a pressure p exceeding an overload resistance of the pressure sensor 5 and/or as a pressure-resistant sensor housing 1 with respect to pressures p of up to 2000 bar.
  • the housing wall 25 preferably has a wall thickness that is predetermined as a function of its geometry and the material of the housing wall 25, by means of which a pressure resistance corresponding to the desired pressure resistance of the sensor housing 1 is ensured.
  • a pressure resistance of the sensor housing 1 that exceeds the overload resistance of the pressure sensor 5 offers the advantage that the sensor housing 1 can withstand pressures p that lead to the destruction of the pressure sensor 5 . This ensures that these extreme overloads cannot penetrate through the sensor housing 1 and thus also cannot cause any damage outside of the sensor housing 1 or in the vicinity of the pressure measuring transducer.
  • the desired hydrogen diffusion tightness of the sensor housing 1 can also be ensured at the same time via a corresponding dimensioning of the wall thickness.
  • the hydrogen diffusion tightness of the sensor housing 1 that can be achieved by dimensioning the wall thickness of the sensor housing 1 accordingly offers the advantage that any hydrogen contained in the medium cannot pass through the sensor housing 1 and therefore cannot cause any impairments outside of the sensor housing 1 either.
  • the pressure sensor can, for example, include a process connection 27, such as the flange shown in Fig. 1 formed there on the sensor housing 1, by means of which the pressure sensor can be mounted on a process connection that carries the medium and is provided at the place of use.
  • a process connection 27 such as the flange shown in Fig. 1 formed there on the sensor housing 1
  • the pressure sensor can be mounted on a process connection that carries the medium and is provided at the place of use.
  • process connection variants that are known from the prior art and are suitable for installing the pressure measuring transducer and/or for pressurizing the interior 3 can also be used.
  • the pressure sensor 5 is designed, for example, as an absolute pressure sensor, which metrologically detects the pressure p acting on the two measuring bodies 13 , 15 as an absolute pressure compared to an internal pressure prevailing in the pressure chamber 11 .
  • a vacuum pressure is particularly suitable as the internal pressure.
  • the pressure chamber 11 enclosed between the measuring bodies 13, 15 is evacuated.
  • an internal pressure that is lower than the pressure p to be measured such as an internal pressure of the order of magnitude of 1 bar, can also be used as the internal pressure.
  • an internal pressure that is lower than the pressure p to be measured such as an internal pressure of the order of magnitude of 1 bar, can also be used as the internal pressure.
  • the internal pressure of 1 bar which corresponds to atmospheric pressure in terms of magnitude, offers the advantage that it is much easier to adjust in terms of production technology than a vacuum pressure.
  • absolute pressure sensors do not require a reference pressure supply running through the housing wall 25 and one of the two measuring bodies 13, 15 to pressurize the pressure chamber 11 with a reference pressure. This offers the advantage that with a corresponding pressure resistance of the sensor housing 1 even an overload leading to the destruction of the pressure sensor 5 cannot penetrate through the sensor housing 1 .
  • the two measuring bodies 13, 15 are connected, for example, by means of a pressure-resistant connection 29, which connects an outer edge of one measuring body 13 to an outer edge of the other measuring body 15 and surrounds the pressure chamber 11 on all sides on the outside.
  • Active brazing for example, such as active brazing produced by means of a zirconium-nickel-titanium active brazing solder, is suitable as a pressure-resistant connection 29 in conjunction with measuring bodies 13, 15 made of ceramic.
  • connection 29 is designed, for example, as a pressure-resistant and hydrogen-diffusion-tight connection.
  • connection 29 is designed, for example, as a glass soldering.
  • the pressure-resistant and hydrogen-diffusion-tight connection 29' of the two measuring bodies 13, 15 can be achieved, e.g. in the manner shown in FIG which is connected to both measuring bodies 13, 15 by a hydrogen-diffusion-tight joint 33, such as a weld produced by means of a ceramic welding process, such as laser welding.
  • a laser welding method that can be used for laser welding ceramic measuring bodies 13, 15 is described, for example, in DE 10 2011 004 722 A1.
  • the ring 31 can be designed as an integral part of one of the two measuring bodies 13 or 15 , which is connected to the other measuring body 15 or 13 by the hydrogen-diffusion-tight joint 33 .
  • connection 29, 29' as a hydrogen-diffusion-tight connection is particularly advantageous when the pressure sensor 5 is designed as an absolute pressure sensor and the pressure sensor is used to measure the pressure of media containing hydrogen.
  • the pressure sensor 5 is designed as an absolute pressure sensor and the pressure sensor is used to measure the pressure of media containing hydrogen.
  • the comparatively thick measuring bodies 13, 15, which also form a long-term stable, high-quality hydrogen diffusion barrier due to the extremely low hydrogen diffusion rate of hydrogen in ceramics, they offer the advantage that high-quality, permanent protection of the pressure chamber 11 against hydrogen penetrating into the pressure chamber 11 given is. This offers the advantage that even over very long periods of time Pressures p of hydrogen-containing media can be measured without the achievable measurement accuracy being adversely affected.
  • the pressure transducer is designed to measure very high pressures p, such as pressures p of greater than or equal to 400 bar and/or pressures of up to 1000 bar or even higher.
  • the base area and thickness d of the two measuring bodies 13, 15 are preferably measured as a function of the pressure measuring range and, if necessary, also of a desired overload resistance of the pressure sensor 5.
  • each of the two disc-shaped measuring bodies 13, 15 has, for example, a base area of 200 mm 2 to 1300 mm 2 and/or a thickness d of 5 mm to 10 mm.
  • a thickness d of greater than or equal to 5 mm offers the advantage that the measuring bodies 13, 15 easily withstand overloads exceeding the upper limit of the pressure measuring range of 1000 bar.
  • the overload resistance is the greater, the smaller the deflectable base area and the greater the thickness d of the measuring bodies 13, 15.
  • a thickness d of less than or equal to 10 mm ensures that the sum of the pressure-dependent deformations of both measuring bodies 13, 15 is large enough to withstand pressures p that are far below the upper limit of the pressure measuring range, such as pressures p of 400 bar to 1000 bar to be able to measure comparatively high measurement accuracy.
  • the change in distance of 4.3 ⁇ m resulting from a pressure change from 400 bar to 1000 bar in the first example and the change in distance of 13.9 ⁇ m resulting from a pressure change from 400 bar to 1000 bar in the second example are examples the changes in distance between the centers of the measuring body that occur over the pressure measurement range are large enough to For example, to achieve a comparatively high measuring accuracy by means of the capacitive converter based on the distance between the two measuring bodies 13, 15 dependent measuring capacitance Cp.
  • the overload resistance can be increased, e.g. by increasing the thickness d of the measuring bodies 13, 15 to thicknesses d of greater than or equal to 10 mm and/or by reducing the pressure-dependent deformable areas of the Measuring body 13, 15 can be achieved.
  • the reduction of the pressure-dependent deformable areas of the measuring bodies 13, 15 can be achieved, for example, by a corresponding increase in the radial width of the ring-shaped connection 29, 29' connecting the outer edges of the measuring bodies 13, 15.
  • Such a widening of the connection 29, 29' also offers the advantage that this increases the hydrogen diffusion tightness of the connection 29, 29'. The latter is particularly advantageous when the connection 29 is in the form of active brazing.
  • the pressure sensor 5 is mounted on the connecting elements 9 that are freestanding in the interior space 3 .
  • the pressure sensor 5 is connected, e.g. A joint, such as soldering, for example, is suitable as the mechanical connection 35 .
  • the connecting elements 9 are designed, for example, as straight, curved or rod-shaped elements having a different shape.
  • the connecting elements 9 have, for example, a free-standing length L of 1 mm to 10 mm in the interior 3 of the sensor housing 1 and/or a cross-sectional area of 0.05 mm 2 to 7 corresponding to a diameter of 0.25 mm to 3 mm mm 2 on.
  • connection elements 9 are each designed as electrically conductive connection lines, the ends of which are each connected to an associated electrical connection 37 of the pressure sensor 5 arranged in the interior 3 by means of the mechanical connection 35 embodied as an electrically conductive connection in this case.
  • connections 37 are electrical connections 37 of the electromechanical converter, which are arranged on an outer surface of the pressure sensor 5.
  • the connections can also include at least one connection of the sensor electronics 17 connected to the converter.
  • Connection elements 9 made of a metal, such as e.g.
  • Connection elements 9 made of Kovar®, stainless steel, nickel, copper, a nickel-iron alloy, a copper-nickel alloy, molybdenum, Alumel® or constantan.
  • the one in the interior is optional free-standing length L of the connecting elements 9 designed as connecting lines is surrounded on the outside by a casing, such as an insulation.
  • the connecting elements 9 designed as connecting lines are each guided through the housing wall 25 by a pressure-resistant, electrical bushing 39 inserted into the housing wall 25 , electrically insulated from the housing wall 25 .
  • Suitable as pressure-resistant bushings 39 are, in particular, bushings 39 that are pressure-resistant to pressures p exceeding an upper measuring range limit of pressure sensor 5, to pressures p that exceed an overload resistance of pressure sensor 5, and/or to pressures p of up to 2000 bar.
  • the bushings 39 are each arranged, for example, in a housing wall area 41 of the sensor housing 1 opposite the opening 7 .
  • 1 shows an example in which the sensor housing 1 is designed as an essentially top-shaped housing, in the housing base of which, which is opposite the opening 7 , the bushings 39 are inserted.
  • Particularly suitable as pressure-resistant bushings 39 are bushings such as ceramic bushings or glass bushings, which are also impermeable to hydrogen diffusion.
  • Glass and ceramic feedthroughs are known from the prior art and, in addition to their high hydrogen diffusion tightness due to the low diffusion rate of hydrogen in ceramics or in glass, offer the advantage that, depending on the design, they can withstand very high pressures, such as pressures of up to 1700 bar or even up to 2000 bar.
  • Corresponding ceramic bushings are offered, for example, by Alumina Systems GmbH, based in Redwitz, Germany, and by CeramTec GmbH, based in Plochingen, Germany.
  • Suitable glass bushings are offered, for example, by the company HaTec Halebitechnik based in Würzburg, Germany.
  • the converter of the pressure sensor 5 is connected to the sensor electronics 17 arranged here outside the sensor housing 1 via the connecting elements 9 designed as connecting lines.
  • This variant offers the advantage that the pressure measurement range is not limited by the pressure resistance of the sensor electronics 17, which is generally lower than the pressure resistance of the pressure sensor 5 and the sensor housing 1.
  • the sensor electronics 17 are preferably arranged directly on the outside of the sensor housing 1 facing away from the interior 3 . As a result, the line length of the electrically conductive connection between the converter and the sensor electronics 17 is kept short. Shorter line lengths offer the advantage that this reduces the influence of electromagnetic interference signals and/or parasitic capacitances on the measurement accuracy that can be achieved.
  • Fig. 3 shows a view of the inside of the measuring body 13 from Fig.
  • connection 29 shown in dashed lines in Fig. 3 between the two measuring bodies 13, 15 is electrically conductive
  • the counter-electrode 21, which is arranged on the measuring body 15 opposite the measuring electrode 19 and is in electrically conductive contact with the connection 29, can also be connected via a Fig. 3 shown measuring body 13 are contacted through to the connection 29 running contact pin Kg.
  • an electrically insulating connection 29, 29' such as a glass soldering or the ring 31 shown in FIG Option shown way done.
  • the contact pin Kg for contacting the counter-electrode 21 extends through one of the two measuring bodies 13 and the electrically insulating connection 29' to a region of the counter-electrode 21, which is attached to an end face of the connection 29' that faces away from the measuring body 13 surrounding the contact pin Kg. adjacent.
  • FIG. 4 shows a modification of the pressure sensor from FIG. 1 , in which the connections 37 of the pressure sensor 5 are arranged on opposite outer sides of the pressure sensor 5 .
  • the measuring electrode 19 is connected via the contact pin Km, which runs through one of the measuring bodies 13, to the connection 37 arranged on the outside of this measuring body 13, and the counter-electrode 21 is connected via the contact pin Kg, which runs through the other measuring body 15, to the connection on the Outside of the other measuring body 15 arranged terminal 37 connected.
  • the modification shown in Fig. 1 the modification shown in Fig.
  • a reference capacitor with a capacitance that is essentially pressure-independent which comprises at least one electrode which is connected via a contact pin running through one of the measuring bodies 13, 15 is connected to a terminal arranged on an outside of the pressure sensor 5 .
  • the pressure sensor includes measuring electronics 43 connected to the sensor electronics 17, which are designed to determine and make available a pressure measurement result p ge m based on the measurement signal.
  • Measuring electronics known from the prior art can be used for this purpose.
  • the measuring electronics 43 shown as an example in Fig. 1 comprises signal conditioning 45 and signal evaluation 47 downstream of signal conditioning 45.
  • Signal conditioning 45 is designed, for example, to amplify the measurement signal, to filter out interference signals contained in the measurement signal and/or to reduce the measurement signal smooth.
  • the signal evaluation 47 is designed to determine and make available the pressure measurement result p ge m on the basis of the processed measurement signal.
  • the measuring bodies 13, 15 of the pressure sensors described with reference to FIGS. 1 to 4 can consist of a different insulator, such as glass.
  • the joint 29 shown in Figure 1 is, for example, a glass solder.
  • measuring bodies 13, 15 made of glass can be connected, e.g. via the connection 29' described with reference to FIG.
  • the ring 31 is a glass ring, for example, which is connected to one of the two measuring bodies 13, 15 or to both measuring bodies 13, 15 via one of the joints 33 shown in FIG. 2, such as a joint designed as glass soldering.
  • pressure sensors whose measuring bodies 13', 15' are made of a metal, such as stainless steel.
  • 5 shows an example of a pressure sensor with two metal measuring bodies 13′, 15′ connected to one another, including the pressure measuring chamber 11, via a connection 49, such as a weld.
  • This pressure sensor is also designed, for example, as a capacitive pressure sensor.
  • the pressure sensor shown in Fig. 5 differs from the pressure sensors 5 shown in Figs. 1 and 4 essentially only in that the electrodes of the converter, such as the measuring electrode 19 shown in Fig. 5 and the counter-electrode 21 shown in Fig.
  • each with the interposition of an insulator 51 on one of the two opposite inner sides of the metallic measuring body 13 ', 15' are arranged.
  • 5 shows insulators 51 as an example, each of which is designed as an inlay inserted into one of the two measuring bodies 13', 15', such as an inlay made of glass or ceramic.
  • the electrical connection of the converter is made, for example, via connecting lines 53 connected to the electrodes, such as measuring electrode 19 and counter-electrode 21, which are electrically connected to the respective measuring body 13', 15 'Insulating bushing 55 is connected through to one of the connections 37 arranged on one of the outer sides of the pressure sensor.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Ceramic Engineering (AREA)
  • Health & Medical Sciences (AREA)
  • Child & Adolescent Psychology (AREA)
  • Measuring Fluid Pressure (AREA)
  • Pressure Sensors (AREA)

Abstract

L'invention se rapporte à un transducteur de pression, en particulier à un transducteur de pression résistant aux surcharges, destiné à mesurer une pression (p). Ledit transducteur comprend un capteur de pression (5) qui est disposé dans l'espace intérieur (3) d'un boîtier de capteur (1), peut être sollicité à travers une ouverture (7) dans le boîtier de capteur (1) par un milieu soumis à la pression (p) à mesurer, et grâce auquel des pressions élevées, en particulier des pressions allant jusqu'à 1000 bars, d'un milieu soumis à la pression à mesurer, en particulier un milieu contenant de l'hydrogène, peuvent être mesurées avec un degré élevé de précision de mesure. Le présent transducteur de pression est caractérisé en ce que : le capteur de pression (5) est monté sur des éléments de raccordement (9) qui font saillie dans l'espace intérieur (3) et sont autonomes dans l'espace intérieur (3) de telle sorte que le capteur de pression (5) est exposé de tous les côtés à la pression (p) régnant dans l'espace intérieur (3) ; le capteur de pression comprend deux éléments de mesure en céramique (13, 15, 13', 15') reliés l'un à l'autre, qui entourent une chambre de pression (11), et sont chacun déformables par la pression (p) agissant sur ces derniers ; et le capteur de pression comprend un transducteur électromécanique qui convertit une variable mécanique dépendant d'une somme des déformations dépendant de la pression des deux éléments de mesure (13, 15, 13', 15') en une variable de mesure électrique pouvant être détectée de manière métrologique.
EP21820506.0A 2020-12-08 2021-11-25 Transducteur de pression Pending EP4260034A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE102020132687.4A DE102020132687A1 (de) 2020-12-08 2020-12-08 Druckmessaufnehmer
PCT/EP2021/082989 WO2022122397A1 (fr) 2020-12-08 2021-11-25 Transducteur de pression

Publications (1)

Publication Number Publication Date
EP4260034A1 true EP4260034A1 (fr) 2023-10-18

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Application Number Title Priority Date Filing Date
EP21820506.0A Pending EP4260034A1 (fr) 2020-12-08 2021-11-25 Transducteur de pression

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US (1) US20240019329A1 (fr)
EP (1) EP4260034A1 (fr)
CN (1) CN116670481A (fr)
DE (1) DE102020132687A1 (fr)
WO (1) WO2022122397A1 (fr)

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5817421B2 (ja) * 1979-02-02 1983-04-07 日産自動車株式会社 半導体圧力センサ
JPS58107682A (ja) * 1981-12-21 1983-06-27 Mitsubishi Electric Corp 半導体圧力検出装置
JPH01284727A (ja) * 1988-05-11 1989-11-16 Toyota Autom Loom Works Ltd 半導体圧力センサ
DE10334854A1 (de) 2003-07-29 2005-03-10 Endress & Hauser Gmbh & Co Kg Drucksensor
DE102006056173A1 (de) 2006-11-27 2008-06-05 Endress + Hauser Gmbh + Co. Kg Trennmembran für hydraulische Druckmittler sowie Druckmittler und Druckmessgeräte mit solchen Trennmembranen
DE102011004722A1 (de) 2011-02-25 2012-08-30 Endress + Hauser Gmbh + Co. Kg Keramische Druckmesszelle
DE102018123041A1 (de) 2018-09-19 2020-03-19 Endress+Hauser SE+Co. KG Druckmesseinrichtung

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WO2022122397A1 (fr) 2022-06-16
CN116670481A (zh) 2023-08-29
DE102020132687A1 (de) 2022-06-09
US20240019329A1 (en) 2024-01-18

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